Bridging plug and retrieving tool therefor



April 6, 1937. A. J. zscHoKKE BRIDGING PLUG AND RETRIEVING TOOL THEREFOR Filed July 15, 1955 2 Sheets-Sheet 1 frm/,e ZSCHO/r/ff Y. Il

a5 a d a www a j w52 W f 5 w s a 5 a M 5 176/ 6 a e 4 5 4 /.f Z 2 L 65W if April 6, 1937- A. J. zscHoKKE BRIDGING PLUG' AND RETRIEVING TOOL THEREFOR Filed July l5, 1955 2 Sheets-Sheet 2 gmc/whoa Afef/wf J Z50/mmf Patented Apr.. 6, 1937b BmnGING PLUG AND aE'rarEvxNG Toor.V

'rnaaaroa Arthur J. Zschokke, Huntington Park, Calif., assignor to The Technicraft Engineering Corporation, Los Angeles, Calif.,

California a corporation of Application July 1s, 1935, semi No. 31,391

15 Claims.

My invention relates to bridging plugs and retrieving tools therefor, and the objects of my invention are:

First, to provide a novelly coacting bridging plug and retrieving tool wherein the retrieving tool manipulates the bridging plug to position its parts in clear of the surrounding casing and restrair'isy the plug in such condition for removal.

Second, to provide a retrieving tool which is particularly adapted for use in conjunction with the bridging plug and setting tool disclosed in, my copending application Serial No. 31,392, filed July 15, 1935.

Third, to provide a removable bridging plug which vincorporates a novel clutch mechanism for holding the part of the plug in their set or securing position, which although protected against release by reason of accidental engagement, is readily accessible to a special retrieving tool.

Fourth, to provide a retrieving tool which is hydraulically operated and may be associated with either a tubing string or special pump mechanism adapted to be lowered with the retrieving tool on a cable, the retrieving tool being in the nature of an operating head adapted to be used interchangeably with the setting tool disclosed in the afore-mentioned copending application.

Fifth, to provide a retrieving tool which may 304 be operated mechanically to release the bridging plug.

With these and other objects in view as may appear hereinafter, attention is directed to the accompanying drawings in which:

Fig'. 1 is a partially elevational, partially sectional view of a bridging plug in positionwithin a well casing and the retrieving tool inits one form thereabove about to engage the plug.

Fig. 2 is an enlarged fragmentary sectional view of the bridging plug and tool taken substantially through 2--2 of Fig. 1 and showing the retrieving tool in engagement with the bridging plug but before being operated to release the plug. Fig. 3 is an enlarged partially elevational, partially transverse sectional view through the gear pump unit, taken through 3-3 of Fig. 2. Fig. 4 is a transverse sectional view through 4-4 of Fig. 2 showing the clutch mechanism for 5o restraining the push rod from return movement. Fig. 5 is another transverse sectional view through 5--5 of Fig. 2 showing the wicker in the head of the plug and the wicker engaging fingers. Fig. 6 is a fragmentary partially elevational. partially sectional view of a modied form of my retrieving tool wherein hydraulic pressure is introduced through a tubing string.

Fig. '1 is a longitudinal sectional view of a further modiiied form of my retrieving tool this construction being mechanically operated and shown in conjunctionwith a modified form of bridging plug, and in the position assumed upon releasing the packing element and lower slips of the bridging plug but before application of an upward force to free the upper slips.

Fig. 8 is an enlarged fragmentary sectional view thereof through 8-8 of Fig. '1, but with the parts in the positions assumed during withdrawal of the bridging plug.

Fig. 9 is a transverse sectional view through 9 9 of Fig. 8 showing the clutch mechanism of the bridging plug.

Two constructions of bridging plugs are i1- lustrated which, while set differently, are practically identical insofar as their coaction with the retrieving tool is concerned and may be used interchangeably with forms of the retrieving tool illustrated. Y

In each of the constructions shown, the bridging plug is built up around a tubular body member I of uniform diameter which is screwthreaded at its lower end to receive a packer body 2.

The packer body comprises a cylindrical upper portion 2a somewhat larger in diameter than the body member I and which is adapted to receive a packing member 3 which may be in the form of a. sleeve with its bore beveled at its upper and lower ends. Below its cylindrical portion 2a, lthe packer body 2 is enlarged in diameter to conform to the bevel of the lower end of the packing member for expanding the same as indicated by 2b. The lower end of the packer vbody is closed.

Above the packer body 2, the body member l receives a lower slip expanding cone 4. Said cone comprises an elongated frusto-conical slip expanding surface la, terminatingat its upper end in a ange 4b whichis undercut at its under side. An annular rib la formed on the body member engages the upper end of the cone to limit upward movement thereof. The lower part Aof the cone 4 is enlarged internally to fit over the cylindrical portion of the packer body 2 and is beveled at its lower extremity, as indicated by 4c to engage the upper end of the packing memf ber 3.

Various conventional packer members whether of the sleeve or multiple ring type may be used. At the upper end of the body member I is sldably fitted an upper slip expanding cone 5 likewise having an elongated fruSto-conical slip expanding surface 5a. and terminating at its lower end in a flange 5b the upper side of which is undercut. The slip expanding surfaces of the two cones converge toward each other, and are adapted to be engaged by arcuate, Wedge-shaped slips 6 having teeth 6a in their outer sides. Two sets of slips are provided, one for each cone. A strap or rein 'I connects each corresponding pair of slips by their larger ends. The several reins are secured at their mid-portions to a. collar 8 which slidably ts the body member I. The por- -tion of each rein between the collar and lower slip is preferablycorrugated as indicated by Ia or otherwise rendered yieldable to compression stresses.

In the construction shown in Figs. 1 through 6 the upper cone 5 extends above the body member I and its bore is enlarged to receive a clutch mechanism 9. Said clutch mechanism comprises a collar 9a which is screwthreaded on the upper end of the body member and is provided at its outer side. With an upwardly dlverging clutch surface 9b. Fitted between the clutch surface and the surrounding wall of the upper cone 5 are a plurality of segmental clutch slips 9c, the inner sides of which slope in conformity with the clutch surface 9b and the outer sides of which are parallel with the axis of the upper cone 5 and conform to its bore. The upper ends of the clutch slips 9c overhang the upper end of the clutch collar 9a and a spring 9d is mounted therebetween to urge the clutch slips upwardly. A guard ring 9e loosely rests on top of the clutch slips.

The collar 9a of the clutch member 9 ts on the outside ofthe body member I and forms a shoulder for miting upward movement of the upper cone.

In the construction shown in Fig. 7 through 9, the upper cone likewise extends above the body member but its bore is not enlarged, and instead a clutch mechanism III, in most respects similar to the clutch mechanism 9, is provided. The clutch mechanism III includes a clutch collar Illa which screws within the upper end of the body member and is provided on its outer face with an upwardly diverging clutch surface |0b. Fitted between this surface and the surrounding wall of the upper cone 5 are a plurality of segmental clutch slips "ic similar to the clutch slips 9b. A spring Illd is provided between the lower ends of the clutch slips |0c and upper end of the body member and surrounding the clutch collar Illa. As in the clutch mechanism 9 the upper ends of the clutch slips Illc overhang the upper end of the clutch collar and may or may not be provided with the guard ring 9e.

In the construction shown in Figs. 7 through 9, the b ody member I is provided with diametrically disposed slots Ib through which extends a cross pin II the ends of which are anchored in the upper cone 5. To the cross pin is attached one end of a spring I2 which extends downwardly through the body member and is suitably anchored to the closed end of the packer body. The spring I2 tends to hold the parts of the bridging plug in their set position.

In the rst construction shown in Figs. 1 through 6, the bridging plug is adapted to be set by the setting tool disclosed in my copending application mentioned hereinbefore. The second construction of bridging plug is designed to be set by another type of setting tool which is inexpensively operated but which forms no part of the present application. Part of such setting tool, in the form of a yoke I3, remains attached to the plug, straddling the spring I2 and secured to the pin II as shown in Fig. '7.

The embodiment of the retrieving tool shown in Figs. 1 through 5 is adapted to be supported from a conductor core cable 2|. In this construction, the cable is equipped with a cable head 22 which provides a mechanical and an electrical connection with an electrical motor 23 of any suitable construction capable of operating while submerged. The motor is preferably provided with a cylindrical housing which is connected at its lower end to a tube section 24. The tube section is in turn joined to a gear pump unit 25, encased within a housing 25a. The gear pump is provided with a centrally disposed driving gear 25h connected with the shaft 23a. of the motor 23 and one or more driven or idler gears 25e arranged therearound. Intake ports 25d extend into the housing 25a. from the outside to admit well1 fluid to the gears of the pump. Discharge ports 25e lead downwardly from the pump and pierce the lower end of the housing 25a.

The lower end of the pump housing 25o, is secured to and closes the upper end of a cylinder 26. 'I'he cylinder 26 receives a piston 21 from which extends a depending piston rod 28. A collar 29 is screwthreaded into the lower end of the cylinder 26. A spring 35 tends to hold the piston 21 in a raised position.

The foregoing parts of the retrieving tool may be identical to an embodiment of the setting tool disclosed in my copending application designated hereinbefore, and the following parts and portions may constitute an operating head which is interchangeable with the operating head of said setting tool.

The lower end of the piston rod 28 receives a push rod 30 which is, in effect, a continuation thereof. The push rod 3U terminates in a head 30a having a conical lower face and adapted to fit within the upper cone'5 of either bridging plug construction. The conical head 30m is designed to engage the guard ring 9e or clutch slips IIlc as the case may be to release the clutch mechanism and permit downward movement of the body member I with respect to the upper cone 5.

'Ihe collar 29 is adapted to receive a tting 3| having an upwardly extending externally threaded boss 3Ia. The fitting 3| is provided with a bore 3|b through which extends the piston rod an push rod. The upper end of the bore 3Ib receives a clutch collar 32a of a clutch mechanism 32. Said collar is provided with an upwardly converging bore spaced from the piston rod. Between the piston rod and clutch collar are itted several arcuate clutch slips 32h the upper ends of which are flanged and are yieldingly held in an upper position by means of a spring 32e. 'I'he clutch mechanism 32 permits downward movement of the piston rod and push rod with respect to the cylinder 26 but prevents return movement thereof and thereby serves to lock the push rod in an extended position.

The tting 3| is provided with a depending sleeve 33 adapted to bear against the upper end of the cone 5. Within the sleeve, there are provided several ngers 34 comprising rein portions 34a secured to the tting 3| and wicker engaging elements 34h depending from the rein 'oortions. 'I'he wicker ngers are adapted to pass within the cone 5. The bore of said cone 5 is provided at its upper portion with internal wickuntil .the wicker ngers have engaged theJ notches 5c of the `upper cone. The motor is then operated so as to drive ,the gear pump which draws in the surrounding well iiuid and applies it at a higher pressure against the pisf l5 ton to force the piston downward relative to its cylinder. By utilizing the well fluid itself to operate the piston, the pump is not required to overcome the hydrostatic pressure but merely creates a pressure difference on opposite sides 20 of the piston.

The cylinder is prevented from rising with respect to the bridging plug by reason of interengagement with the upper cone. The push rod forces the clutch mechanism 9 or I0 into a released position and thereafter both urges the cones away from each other and the packer body away from the lower cone so as to loosen the bridging plug and return slips to their' interlocking relationship with the undercut anges 4b and 5b. During this operation, an upward tension on the cable facilitates release of the upper cone, also, the cylinder 26 tends to move upwardly and consequently tends to raise the upper cone.

In the construction shown in Fig. 6 the operating head, including the cylinder, piston, and piston rod, is identical with the above. In place of the electro-hydraulic means of operation, the

cylinder 26 is connected with a tubing string 4I by means of an adapter'collar 42. The piston when so connected with a tubing string is operated by creating either pneumatically or hydraulically a pressure within the tubing string in excess of the hydrostatic pressure. After the piston has moved from its initial position it does not return until the plug has been raised to the surface and the apparatus disassembled; therefore, bleeder or relief ports 42 may be provided in the adapter collar 42 to permit draining of the pressure liquid, if such is used, as the tubing string is lifted, such ports being sufficiently small to offer no material handicap in the operation of the piston.

A third construction of my retrieving tool is shown in Figs. 7 through 9. The arrangement here illustrated is operated mechanically largely by the weight of a tubing string or weight bar attached to a sand line. A tubing string or weight bar 5I is secured to a plug fitting 52 which is in turn secured to the upper end of a tube section 53. The tube section is attached to a sleeve 54.

The sleeve 54 receives a push rod 55 at the upper end of which is provided a disk 55a positioned within the tube section 53. A strong spring 56 is disposed between the disk 55a and the plug fitting 52 in such a manner that the push rod normally occupies an extended position. The lower end of the push rodis provided with an operating head 55h having a conical lower end adapted to enter the upper cone 5 and engage the clutch mechanism 9 or Ill.

The sleeve 54 also supports a plurality of depending wicker engaging fingers 51 compris- 7.5 ing wicker engaging teeth 51a at their lower 3l and by thei portions and spring reins at their upper portions. 'I'he ilngers 51 are adapted to enter the upper cone 5 and engage its wicker notches 5c as in the first described structure and their inward movement is limited by a guard shell 58 secured to the sleeve 54 and surrounding the upper portions of the fingers 51. Said guard shell engages the top of the top cone 5.

While in the hydraulically operated arrangements, the conical extremity of the push rod head occupied an initial position adjacent the ngers so that said ngers engaged the wickers before operation of the push rod; inthe present construction, the extremity of the push rod head is spaced downwardly from the fingers and must force the body'member downwardly before the ngers can engage. The normal distance between the extremity of the push rod vhead and the fingers is more than the relative movement of the body member and upper cone required to pack the packing element and set the slips and yice versa.

Operation of the last described structure is as follows:

The retrieving tool is lowered into engagement with the bridgingplug. The push rod head enters the cone 5 and engages the clutch mechanism to release it. Suflicient weight is applied to force the packing body downward until the packing element is released and to force the lower cone clear of the lower slips. This weight holds the slips of the upper cone set. When the push rod has traveled sufficiently to release the packing element and the lower slips, the remaining movement is taken up by the spring 56 until the wicker engaging ngers 51 interlock with the wicker notches of the upper cone as shown in Fig. 7. The retrieving tool is then raised and the spring 56 is then free to cause further relative movement of the body member and upper cone to free the upper slips and move them from the position shown in Fig. 7 to that shown in Fig. 8. In effect the upper cone is pulled upwardly directly with the weight bar or tubing string, while the spring 56 holds the body member down until the upper slips return to their initial positions.

It should be noted that the spring 56 is made suiiiciently stiff to overcome the setting spring I2, but when used in conjunction with the bridging plug shown in Figs. 1 through 6 a weaker spring may be used.

Though I have shown and described certain embodiments of my invention, I do not wish t0 be limited thereto but desire to include in the scope of my invention the constructions, combinations, and arrangements as set forth in the appended claims.

I claim:

1. In a well tool;- an implement adapted to be secured within a well bore and including, a hollow member forming the upper end of the implement and provided with vwickers, a slidable element within said member below its upper end, securing means for said implement associated with said element and member and responsive to downward movement of said element relative to said member to release said implement; and a retrieving tool for said implement including, a device adapted to enter said hollow member and thrustingly engage with said element, and means engageable with the wickers of said hollow member.

2. In a well tool; an implement adapted to be secured within a well bore and including .ele-

ments adapted when moved relatively to release the implement; a retrieving tool for said implement including, means thrustingly engageable with one of said elements, a device retractably engageable with another of said elements, hydraulic means for causing relative movement o1 said means and device whereby said elements are moved relatively to release saidimplement.

3. In an apparatus of the class described; a. retrieving tool comprising, a thrust member, a retracting member, and a hydraulic means for causing relative movement of said members; and an implement adapted to be secured within a well bore and including, elements adapted to be operatively associated with said members and movable thereby to release the implement, and an instrumentality associated with said elements to restrain said elements against such releasing movement, said instrumentality being interposed between one of said elements and its coacting member and engageable by said member to be thereby rendered inoperative.

4. In an apparatus of the class described; a retrieving tool comprising, a thrust member, `a retracting member, a piston and cylinder means connected with said members to cause relative movement thereof, a pump for supplying pressure to said means, and an electric motor for actuating said pump; and an implement adapted to be secured within a well bore and including, elements adapted to be operatively associated with said members and movable thereby to release the implement, and an instrumentality associated with said elements to restrain said elements against such releasing movement, said instrumentality being interposed between one of said elements and its coacting member and engageable by said member to be thereby rendered inoperative.

5. In an apparatus of the class described; a retrieving tool comprising a thrust head, and attaching means positioned thereabove; and an implement adapted to be secured within a well bore against movement in either direction including, an element exposed to the upper end of the implement and adapted when moved downwardly to release said implement for upward movement, said thrust head engageable with said element and operable by its weight to force said element downwardly, and Said attaching means thereafter engageable with the upper end of said implement for withdrawal; and an instrumentality associated with said element and normally restraining said element against such downward movement, said instrumentality engageable by said thrust head to be rendered inoperative thereby and permit downward movement of said element.

6. The combination with a bridging plug having a iirst cone and slip means adapted to secure the plug against downward movement, a second cone and slip means for securing the plug against upward movement, an operating element for the second cone and slip means, said operating element being exposed to the upper end of the plug and movable downwardly to release the second cone and slip means; of a retrieving tool comprising, a thrust head engageable with said operating element to release said second cone and slip means while the 'plug is held by the rst cone and slip means; and a device thereafter engageable with the first cone and slip means to release the same.

'7. The combination with a bridging plug having a rst cone and slip means adapted to` secure the plug against downward movement, a second cone and slip means for securing the plug against upward movement, an operating element for the second cone and slip means, said operating element being exposed to the upper end ofthe plug and movable downwardly to release the second cone and slip means; of a clutch mechanism associated with said operating element and the rst cone and slip means tending to restrain said means in their securing positions, said clutch mechanism being accessible from the upper end of the plug; and a retrieving tool comprising, a thrust head engageable with said clutch mechanism to render the same inoperative and thereupon actuate said operating element to release the second cone and slip means while the plug is held by the first cone and slip means; and a device thereafter engageable with the first cone and slip means to release the same.

8. The combination with a bridging plug having a vfirst cone and slip means for securing the plug against downward movement, a second cone and slip means for securing the plug against upward movement, and operating elements for said means accessible from the upper end of the plug; of a retrieving tool comprising, means for forcing said elements relatively to release said cone and slip means, and means for retaining the bridging plug on said retrieving tool for subsequent withdrawal.

9. The combination with a bridging plug having a rst cone and slip means for securing the plug against downward movement, a second cone and slip means for securing the plug against upward movement, and operating elements for said means accessible from the upper end of the plug; of an instrumentality interposed between said elements tending to retain said cone and slip means in their securing positions, and a retrieving tool comprising, means adapted to engage said instrumentality to render the same inoperative and thereupon actuate said operating elements to release said cone and slip means.

10. In a well tool; an implement adapted to be secured within a well bore and including a i-lrst securing device releasable in response to downward movement, and a second securing device movable relative to the first device and releasable in response to upward movement; and a retrieving tool entity adapted to be lowered into engagement with said implement, said retrieving tool including a downward thrusting means for releasing said rst securing device, and an upwardly operating releasing means securable with said second securing device said means being relatively movable.

11. The combination with an implement adapted to be secured within the well and including elements adapted when axially moved relatively to release the implement, and an instrumentality tending to restrain said elements against such relative movement; of a retrieving tool entity for said-implement adapted to be lowered en toto into a well bore and including a device engageable with said instrumentality to render said instrumentality inoperative, a mechanism including members relatively movable axially one of which incorporates said device and operating means for said mechanism adapted to force said elements relatively thereby to release the implement, and means incorporated in the other of said members for retaining the implement on said retrieving tool for subsequent withdrawal from the well bore.

12. In a retrieving tool the combination with;

an implement adapted to be secured within the well and including retrieving tool engaging elements adapted when moved relatively to free the implement, and a releasable instrumentality tending to restrain said elements against such relative movement, of and a retrieving tool adapted to be lowered as a unit into engagement with said implement and including al thrusting device positioned for coaction with one of said elements and with said instrumentality, means vinterlockingly engageable with another of said elements for attaching the implement to the retrieving tool for withdrawal; and mechanism for urging said thrusting device and said means relatively to urge correspondingly the retrieving tool engaging elements of said implement.

13. A bridging plug including a hollow element at its upper end; a slidable element in said hollow element, said elements capable of relative axial movement in one direction to set the plug and a return movement to release the plug; and a clutch mechanism carried by said slidable element and engageable with said hollow element to restrain said elements against return movement, said clutch positioned above said slidable element but within said hollow element and engageable from the upper end of the bridging plug to release the clutch mechanism and permit such return movement of said elements and release of the P1118'.

14. 'I'he combination with a bridging plug including a hollow element at its upper end, and a slidable element in said hollow element, said elements capable of relative axial movement in one direction to set the plug and a return movement to free the plug; of a clutch mechanism positioned above said slidable element but within said hollow element and tending to restrain said elements against such return movement; and a retrieving tool including a thrusting member adapted to enter said hollow member, release said clutch mechanism and thereupon urge said slidable element in a manner to free the bridging plug, and means for retaining the bridging plug on said retrieving tool for withdrawal.

15. In a well tool; an implement adapted to be secured within a well bore and including a hollow member forming the upper end of the implement and incorporating connecting means, a slidable element within said member below its upper end, securing means for said implement associated with said element and member and responsive to downward movement of said element relative to said member; and a retrieving tool for said implement including a device adapted to enter said hollow member and thrustingly engage said element, and means engageable with the connecting means of said hollow member to attach the implement to said retrieving tool.

ARTHUR J. ZSCHOKKE. 

